Blood factors, particularly Factor VIII and Factor IX, are now the standard treatment for diseases caused by a lack of the appropriate factor, in particular hemophilia. The blood factor has generally been derived from human blood by various extraction techniques, for example as disclosed in EP-A-0083483, or by expression in genetically modified microorganisms, for example as disclosed in EP-A-0160457 and EP-A-0182448.
Blood factor products such as Factor VIII are highly delicate, unstable proteins. They are usually supplied in the form of frozen solutions in an appropriate buffer or, more generally, as freeze-dried powders. Even the freeze-dried powders must be kept cold during storage. In order to stabilize the freeze-dried material, commercial products contain a stabilizing protein, in particular human serum albumin (HSA). It has not been thought possible to prepare a dry blood factor composition which is stable at ambient temperatures and at pasteurization temperatures (e.g., 60° C.) in the absence of HSA. However, the presence of HSA introduces considerable problems of purification since it is essential that the protein is free of viral contamination. The use of recombinant HSA to overcome these problems is expensive.